Martinez: Barkley would not benefit from move
Barkley is expected to play a key role in Roy Hodgson's England side at the FIFA World Cup but even if the 20-year-old midfielder stars in Brazil, he will not be leaving Goodison Park if Martinez has his way.
Chelsea are reportedly most interested in luring Barkley away from Everton.
While the obvious reason for Martinez to keep Barkley would be self-interest, the Spanish manager argued he is more focused on what is best for his young charge.
"No, because that would be wrong for him," Martinez said.
"I always feel as a manager, you develop a relationship with players and you're always honest with them.
"Ross is a phenomenal talent, probably the best English talent I have ever seen, but he is not the finished article yet and you need to be very careful.
"It's our duty to protect him and I know Everton is the perfect place for him for the next 12 months."
Martinez also hinted that if Everton could break into the top four of the Premier League next season and qualify for the UEFA Champions League - they finished fifth in 2013/14 - they might be able to tempt the attacking midfielder to stay on Merseyside.
"In football, obviously you can never speak about the future. Obviously we need to come along and try to get into the top four positions to offer players like Ross the next stage of their development," the former Swansea and Wigan manager said.
"But Ross is delighted at Everton and feels very much in the right place at the right time of his career."
Barkley played 38 games in all competitions for Everton this season, scoring seven goals.